(1) Field of the Invention
The present invention relates to a light shielding material in which specific gradient of the luminous density is formed so that transmittance of rays of the visible region is controlled. This light shielding material exerts very excellent effects when it is used as glare-reducing glasses for drivers of automobiles and the like.
(2) Description of the Prior Art
As glare-reducing glasses suitable for driving of automobiles and the like, there are known various glasses. For example, yellow glasses and Nd ion-incorporated lenses are known as glare-reducing glasses for the night driving and colored lenses commercially available as sunglasses or fashion glasses, mirror lenses and polarizing lenses are known as glare-reducing glasses for the daytime driving. It has been pointed out in the art that yellow glasses and Nd ion-incorporated lenses are not satisfactory in the glare-reducing effect in the night driving. In case of colored lenses known as sunglasses, when they are used for the night driving, it is very difficult to maintain a sufficient glare-reducing effect and a sight reduction-preventing effect in combination, and as is well known, lenses having a satisfactory glare-reducing effect are apparently defective in that since the sight is drastically reduced in the night driving, there is inevitably included a risk when they are used for the night driving.